1. Field of the Invention
The present invention relates to a device for use in connection with the control of insects, in particular for monitoring the population of selected species of insects.
2. Prior Art
In order to be able to protect crops adequately it is necessary to be able to determine exactly when any given species of insect begins to pose a threat to them so that measures can be taken to reduce the infestation of that insect, for example, by spraying an appropriate insecticide.
It is important that spraying should take place in good time. Late spraying would not obtain the required results and therefore the usual procedure is to spray as soon as it seems even likely that a rapid proliferation of harmful insects is about to take place. This procedure is not satisfactory, however, since it is expensive and often wasteful inasmuch as spraying sometimes takes place when it is not necessary; it is also unsatisfactory inasmuch as indiscriminate spraying causes a considerable degrading of the environment.
Attempts have been made to avoid these disadvantages by using insect traps which enable a reasonably accurate estimation of the insect population to be made. One known such trap comprises a sheet of thin card on which is placed a synthesised substance, that is pheromone, which in nature is secreted from the female insect in order to attract the males; the synthesised pheromone could be, for example, one of the types produced by the firm Zoecon under the trade names Codlemone, Orfamone and Funemone. The male insect, attracted by the pheromone, lands on the card and remains trapped there by a sticky substance which covers the bottom of the trap. When using this system the farmer must inspect the various traps daily and count those insects of the type with which he is concerned trapped on the card, in order to be able to establish, on the basis of the number of insects caught, and by means of very precise tables, whether the population of the species under examination is rapidly increasing, and therefore whether it is necessary to take any steps to control the proliferation of this insect.
This system has a number of disadvantages; the traps are exposed to all weathers and therefore their efficiency deteriorates; moreover, the farmer has to count, every day without fail, the number of insects caught in each trap, and then has to remove them from the trap with special tweezers, and record the number of insects and the day on which they were trapped so as to be able to monitor changes in the population of these insects.
Clearly all this requires great care and attention, and moreover it constitutes a loss of useful time. The present invention seeks to avoid the above mentioned disadvantages with a device for use in controlling the population of selected species of insects, which is easy to manufacture, of low cost, will not deteriorate significantly under the action of atmospheric agents, and by means of which the number of trapped insects can be counted automatically.